AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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General Description
The AAT4901 FastSwitch™ is a member of AnalogicTech’s
Application Specific Power MOSFET™ (ASPM™) product
family. It is a full-bridge buffered power stage operating
with an input voltage range of 2.0V to 5.5V. The device
is designed to operate with a switching frequency of up
to 2MHz, minimizing the cost and size of external com-
ponents. The AAT4901 is protected from shoot-through
current by integrated break-before-make circuitry. The
drivers can be independently controlled and their propa-
gation delay, from input to output, is typically between
8ns-19ns dependent upon logic option.
Four options are offered providing a single input control,
dual input control or as two independent half-bridges.
Other features include low RDS(ON) and low quiescent cur-
rent allowing for high efficiency performance. The AAT4901
includes thermal protection to safeguard the device under
extreme operating conditions.
The AAT4901 is available in the space-saving, Pb-free
8-pin SC70JW package and is rated over the -40°C to
+85°C temperature range.
Features
• V
IN Range: 2.0V–5.5V
• R
DS(ON):
High-side 220m
Low-side 160m
• Break-Before-Make Shoot–Through Protection
• 4 Options
Single Control Input with Enable
• Two Logic Versions
Dual Control Input with Brake Function
Dual Half-bridge
• Low Quiescent Current:
10A (max) DC
5mA (max) at 1MHz
• Over-Temperature Protection
• -40°C to +85°C Temperature Range
• SC70JW-8 Package
Applications
DC Motor Drive
Door Locks
Dual Low-Side MOSFET Gate Driver
Fan Motors
High Frequency DC/DC Converters
High Speed Line Drive
Proximity Detectors
Typical Applications
AAT4901-1
OUTA
OUTB
IN
GND
ENA
ENB
C
IN
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Pin Descriptions
Pin #
Symbol
Function-1, -2, -4 -3
1 ENA Active high enable signal.
2 IN Supply voltage input; input voltage range from 2.0V to 5.5V.
3 ENB Active high enable signal.
4 N/C ENC 4901-1/-2/-4: No connection.
4901-3: Active high enable signal.
5 GND Ground connection
6 OUTB Output of half-bridge B. Connect to load.
7 OUTA Output of half-bridge A. Connect to load.
8 N/C END 4901-1/-2/-4: No connection.
4901-3: Active high enable signal.
Pin Configuration
SC70JW-8
(Top View)
IN
ENB
N/C
N/C
OUTA
OUTB
GND
ENA 1
2
3
45
6
7
8
IN
ENB
ENC
END
OUTA
OUTB
GND
ENA 1
2
3
45
6
7
8
AAT4901-1/-2/-4 AAT4901-3
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Absolute Maximum Ratings1
Symbol Description Value Units
VIN IN to GND -0.3 to 6.0 V
VEN ENA, ENB, ENC, END to GND -0.3 to VIN + 0.3 V
VOUT OUT to GND -0.3 to VIN + 0.3 V
IMAX Maximum Continuous Switch Current 0.7 A
IMAX(PK) Maximum Peak Current 3 A
TLEAD Maximum Soldering Temperature (at Leads) 300 °C
Thermal Information
Symbol Description Value Units
PD Maximum Power Dissipation (TA = 25°C) 440 mW
ΘJA Thermal Resistance2225 °C/W
TJOperating Junction Temperature Range -40 to 150 °C
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions
specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on a FR4 board.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Electrical Characteristics1
VIN = 5V, TA = -40 to 85°C unless otherwise noted. Typical values are at TA = 25°C.
Symbol Description Conditions Min Typ Max Units
VIN Operation Voltage 2.0 5.5 V
IQAC AC Quiescent Current IN = 5V, ENB (D) = IN,
ENA (C) = 1MHz, IOUT = 0
AAT4901-1 3 5
mA
AAT4901-2 1.6 4
AAT4901-3 1.6 4
AAT4901-4 0.9 2.5
IQDC DC Quiescent Current IN = 5V, ENB (D) = IN,
ENA (C) = GND, IOUT = 0
AAT4901-1
5.5 10.0 A
AAT4901-2
AAT4901-3
AAT4901-4
IQ(OFF) Off-Supply Current
ENB (D) = ENA (C) = GND, IN = OUT
= 5.5V
1.0 A
ISD(OFF) Off-Switch Current
ENB (D) = GND, IN = 5.5V, VOUT = 0, or
OUT = IN
0.03 1 A
RDS(ON)H High Side MOSFET On-Resistance
VIN = 4.5V 220
mΩVIN = 3.0V 250
VIN = 2.0V 340
RDS(ON)L Low Side MOSFET On-Resistance
VIN = 4.5V 160
mΩVIN = 3.0V 180
VIN = 2.0V 240
VONL
ENA (C), ENB (D) Input Low Voltage
0.4 V
VONH
ENA (C), ENB (D) Input High Voltage
1.5 V
VHYS ENA (C), ENB (D) Input Hysteresis 200 mV
ISINK ENA (C), ENB (D) Input Leakage ENA (C) , ENB (D) = 5.5V 0.01 1.0 A
TBBM Break-Before-Make Time ENA (C) Rising 5.0 ns
ENA (C) Falling 5.0 ns
TSHDH
Chip Thermal Shutdown
Temperature
Threshold 145 °C
Hysteresis 25
TON-DLY ENA (C) to OUT Delay
ENA (C) Rising
AAT4901-1 15
ns
AAT4901-2 15
AAT4901-3 8
AAT4901-4 14
ENA (C) Falling
AAT4901-1 18
ns
AAT4901-2 15
AAT4901-3 7
AAT4901-4 19
THIZ ENB to OUT HiZ Delay
ENA (C) = GND
AAT4901-1 12
ns
AAT4901-2 10
AAT4901-3 10
AAT4901-4 12
ENA (C) = IN
AAT4901-1 11
ns
AAT4901-2 10
AAT4901-3 7
AAT4901-4 12
1. The AAT4901 is guaranteed to meet performance specifications over the –40°C to +85°C operating temperature range and is assured by design, characterization, and correla-
tion with statistical process controls.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Typical Characteristics
AAT4901-1 AC Quiescent Current
vs. Input Voltage
(ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25°C)
Input Voltage (V)
AC Quiescent Current (mA)
0.5
1.2
1.9
2.6
3.3
4.0
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
AAT4901-2 AC Quiescent Current
vs. Input Voltage
(ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25°C)
Input Voltage (V)
AC Quiescent Current (mA)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
AAT4901-3 AC Quiescent Current
vs. Input Voltage
(ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25°C)
Input Voltage (V)
AC Quiescent Current (mA)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.0
0.3
0.6
0.9
1.2
1.5
AAT4901-4 AC Quiescent Current
vs. Input Voltage
(ENB = IN; ENA = 1MHz; IOUT = 0A; TA = 25°C)
Input Voltage (V)
AC Quiescent Current (mA)
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
0.0
0.3
0.6
0.9
1.2
1.5
AAT4901-1 AC Quiescent Current
vs. Switching Frequency
(ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25°C)
Switching Frequency (kHz)
AC Quiescent Current (mA)
0.1 1 10 100 1000 10000
0.001
0.01
0.1
1
10
VIN = 5.0V
VIN = 3.0V
AAT4901-2 AC Quiescent Current
vs. Switching Frequency
(ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25°C)
Switching Frequency (kHz)
AC Quiescent Current (mA)
0.1 1 10 100 1000 10000
0.001
0.01
0.1
1
10
VIN = 5.0V
VIN = 3.0V
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
6 4901.2010.01.1.2
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Typical Characteristics
AAT4901-3 AC Quiescent Current
vs. Switching Frequency
(ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25°C)
Switching Frequency (kHz)
AC Quiescent Current (mA)
0.1 1 10 100 1000 10000
0.001
0.01
0.1
1
10
VIN = 5.0V
VIN = 3.0V
AAT4901-4 AC Quiescent Current
vs. Switching Frequency
(ENB = IN; ENA = 0.1kHz~2000kHz; VONH = 2V; IOUT = 0A; TA = 25°C)
Switching Frequency (kHz)
AC Quiescent Current (mA)
0.1 1 10 100 1000 10000
0.001
0.01
0.1
1
10
VIN = 5.0V
VIN = 3.0V
AAT4901-1 AC Quiescent Current
vs. Temperature
(ENB = IN, ENA = 1MHz; IOUT = 0A)
Temperature (°C)
AC Quiescent Current (mA)
0
1
2
3
4
-40 -15 10 35 8560
VIN = 5.0V
VIN = 3.0V
AAT4901-2 AC Quiescent Current
vs. Temperature
(ENB = IN, ENA = 1MHz; IOUT = 0A)
Temperature (°C)
AC Quiescent Current (mA)
0
1
2
3
4
-40 -15 10 35 8560
VIN = 5.0V
VIN = 3.0V
AAT4901-3 AC Quiescent Current
vs. Temperature
(ENB = IN, ENA = 1MHz; IOUT = 0A)
Temperature (°C)
AC Quiescent Current (mA)
-40 -15 10 35 8560
0
1
2
3
4
5
VIN = 5.0V
VIN = 3.0V
AAT4901-3 AC Quiescent Current
vs. Temperature
(ENB = IN, ENA = 1MHz; IOUT = 0A)
Temperature (°C)
AC Quiescent Current (mA)
-40 -15 10 35 8560
0
0.5
1
1.5
2
VIN = 5.0V
VIN = 3.0V
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Typical Characteristics
Low Side RDS(ON) vs. Output Current
(TA = 25°C)
Output Current (A)
RDS(ON)L (mΩ)
0
50
100
150
200
250
300
0.1 0.2 0.3 0.4 0.5 0.6 0.7
VIN = 2.0V
VIN = 3.0V
VIN = 4.5V
High Side RDS(ON) vs. Output Current
(TA = 25°C)
Output Current (A)
RDS(ON)H (mΩ)
0.1 0.2 0.3 0.4 0.5 0.6 0.7
0
50
100
150
200
250
300
350
VIN = 2.0V
VIN = 3.0V
VIN = 4.5V
Low Side RDS(ON) vs. Temperature
(IOUT = 0.7A)
Temperature (°C)
RDS(ON)L (mΩ)
0
50
100
150
200
250
300
350
-40 -15 10 35 60 85
VIN = 2.0V
VIN = 3.0V
VIN = 4.5V
High Side RDS(ON) vs. Temperature
(IOUT = 0.7A)
Temperature (°C)
RDS(ON)H (mΩ)
0
50
100
150
200
250
300
350
400
-40 -15 10 35 60 85
VIN = 2.0V
VIN = 3.0V
VIN = 4.5V
MOSFETs RDS(ON) vs. Input Voltage
(IOUT = 0.7A; TA = 25°C)
Input Voltage (V)
RDS(ON) (mΩ)
0
50
100
150
200
250
300
350
22.533.544.555.5
High Side
Low Side
AAT4901 Enable A/B/C/D Threshold Voltage
vs. Input Voltage
Input Voltage (V)
Enable Threshold Voltage (V)
2 2.5 3 3.5 4 4.5 5 5.5
0
0.2
0.4
0.6
0.8
1
1.2
1.4
VIH, -40°C
VIL, -40°C
VIH, 25°C
VIL, 25°C
VIH, 85°C
VIL, 85°C
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Functional Description
The AAT4901 is a buffered full-bridge driver IC with
options to allow the device to function as two independent
half-bridges. The output stage is capable of driving output
loads of up to 0.7A and features break-before-make tim-
ing and very fast propagation delay time, allowing high
switching speed up to 2MHz. The enable input (EN), when
driven low, turns off the driver and reduces the operating
current to less than 1A. Over-temperature shutdown
protects the AAT4901 in the case of overload or defective
MOSFET. Logic options allow the AAT4901 to be used as a
small DC motor driver with break function, a solenoid
driver, a dual-low-side MOSFET driver, or as a coil driver.
Applications include motor drive, proximity detectors,
electronic locks, and DC-DC converters.
Functional Block Diagram
AAT4901-3 Only
Control Logic
ENA
IN
GND
OUTA
OUTB
ENB
ENC
END
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Options
AAT4901-1
H-bridge configuration with two enables. Enable B is
active high and enables the H-bridge output. Enable A
toggles the H-bridge outputs A and B in anti-phase. In
steady state, this can provide forward/reverse motor
drive signals.
AAT4901-2
H-bridge configuration with two enables. Enable A and
Enable B are in anti-phase and provide forward/reverse
and braking.
AAT4901-3
Dual independent half-bridge configuration with four
enables. Function similar to 2 x AAT4900.
AAT4901-4
H-bridge with two enables. Enable A and Enable B are in
anti-phase and toggle the H-bridge outputs A and B in
anti-phase respectively. In steady state, this can provide
forward/reverse motor drive signals to adjust the motor
speed by various duty cycles.
AAT4901-1/-4 Logic Table
-1 -4
OUTA OUTBENA ENB ENA ENB
0 0 0 0 Hi Z Hi Z
1 0 1 1 Hi Z Hi Z
0 1 1 0 IN GND
1 1 0 1 GND IN
AAT4901-2 Logic Table
ENA ENB OUTA OUTB
0 0 Hi Z Hi Z
1 0 IN GND
0 1 GND IN
1 1 IN IN
AAT4901-3 Logic Table
ENA/C ENB/D OUTA/B
0 0 Hi Z
1 0 Hi Z
01IN
1 1 GND
Timing Diagram
V_ENA
V_OUTA
TON-DLY-R TON- DLY-F
50% 50%
TON- DLY-RTON-DLY - F
50% 50%
THIZ_GND
TON-DLY -R
THIZ_IN
TON- DLY-F
50% 50%
50% 50%
10%
90%
90%
10%
V_ENB
V_OUTB
Hi Z Hi Z
Hi ZHi Z
(OFF)
(OFF)
(OFF)
(OFF)
Figure 1: AAT4901-4 Timing Diagram.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
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Application Information
Input Supply Capacitor
The input capacitor provides a low impedance loop for
the edges of pulsed current drawn by the AAT4901 and
reduces the surge current drawn from the input power.
A 4.7F to 10F X7R or X5R low ESR/ESL ceramic capac-
itor is selected for the input supply decoupling. To mini-
mize the tray resistance, the capacitor should be placed
as closely as possible to the input pin. This keeps the
high frequency content of input current localized, mini-
mizing EMI and input voltage ripple.
Shoot-Through Protection
The internal high-side and low-side MOSFETs of the
AAT4901 cannot conduct at the same time to prevent
shoot-through current. When the high-side MOSFET
turns on, the low-side MOSFET turns off first; after 5ns
break-before-make time, the high-side MOSFET then
turns on. Similarly, before the low-side MOSFET turns
on, the high-side MOSFET turns off; after a certain
break-before-make time (5ns typ.), the low-side MOSFET
turns on. The dead time between the high-side and low-
side turn-on should be kept as low as possible to mini-
mize current flows through the body diode of the high-
side and/or low-side MOSFET(s). The break-before-make
shoot-through protection significantly reduces losses
associated with the driver at high frequency.
Thermal Calculations
In the dual low-side MOSFET driver application, the power
dissipation of the AAT4901 includes the power dissipation
in the MOSFETs due to charging and discharging the gate
capacitance, the AC quiescent current power dissipation,
and transient power in the driver during output transi-
tions. As the transient power is usually very small, its
losses can be ignored. Maximum package power dissipa-
tion can be estimated by the following equation:
Eq. 1: TJ(MAX) - TA
θJA
PD(MAX) = VCC · IIN =
= IQAC · VCC + QG(tot)FSW · VCC
Where:
TJ(MAX) = junction temperature of the dice (°C).
TA = ambient temperature (°C).
JA = thermal resistance (225°C/W).
IQAC = AC quiescent current of the driver (mA).
QG(tot) = total gate charge of external low side MOSFETs
(nC).
FSW = switching frequency (MHz).
The maximum junction temperature for the SC70JW-8
package can be derived from Equation 1:
Eq. 2: TJ(MAX) = PD(MAX) · θJA + T
A
For example, if the AAT4901 drives 2 AAT9560 MOSFETs
whose maximum gate charge is specified as 13nC for
VGATE = 5V, the total power dissipation in the driver at a
switching frequency of 1MHz equals:
PD(tot) = 2 · (5V · 13nC · 1MHz) + 5V · 4.0mA = 150m
W
Gate Drive Current Ratings
Assuming that the maximum gate charge of the dual
low-side MOSFETs are equal, the maximum gate drive
capability for the designed maximum junction tempera-
ture without an external resistor can be derived from
Equation 1:
Eq. 3: 1
2 · FSW
TJ(MAX) - TA
θJA · VIN
QG(MAX) = · - IQAC
The relationship between gate capacitance, turn-on/
turn-off time, and the MOSFET driver current rating can
be determined by:
Eq. 4: IG(MAX) = CG(MAX) · dV
dt
Where:
IG(MAX) = peak drive current for a given voltage
CG(MAX) = maximum gate capacitance
dV = MOSFET gate-to-source voltage
dt = rising time of MOSFET gate-to-source voltage
AAT4901
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The relationship between CG(MAX) , QG(MAX) , and VGATE is
given by:
Eq. 5: QG(MAX)
VGATE
CG(MAX) =
The peak current drive requirements for a given MOSFET
gate voltage can be derived from Equations 4 and 5:
Eq. 6: IG(MAX) = QG(MAX
)
dt
Design Example
VIN = 5V
VGATE = 5V
FSW = 1MHz
JA = 225°C/W
IQAC = 4.0mA
TJ(MAX) = 120°C
TA = 85°C
tRISE = dt = 10ns
1
2 · 1MHz
120°C - 85°C
225°C/W · 5V
QG(MAX) = · - 4.0mA = 13.6nC
⎛⎞
⎝⎠
QG(MAX)
VGATE
CG(MAX) = = = 2.7nF
13.6nC
5V
IG(MAX) = = = 1.36
A
QG(MAX)
dt
13.6nC
10ns
Typical Applications
2-Phase Synchronous Buck Converter
The most common AAT4901 applications include multi-
phase DC/DC converter output power stages, DC motor
drive, a dual low-side MOSFET driver, and a 3-state high-
speed high-current line driver.
Figure 2 shows a typical configuration when used as a
2-phase buck converter power stage with synchronous
rectification. The EN pin can be used to force outputs
OUTA/OUTB to a high impedance state; this allows the
output inductor to operate in discontinuous condition
mode (DCM) and improves efficiency under light load
conditions. The body diode associated with the low-side
switching device gives the AAT4901 inductive switching
capability, and clamps the LX node at one diode drop
below GND during the break-before-make time. The
multiphase buck converter assures a stable, high-perfor-
mance topology for high currents and low voltages which
are demanded in computers, workstation, telecom and
datacom servers. Figure 3 illustrates output ripple cur-
rent reduction due to 2-phase cancellation.
Motor Drive
The AAT4901 is ideally suited for use as an efficient out-
put driver for DC motor control due to its full bridge
output stage with integrated MOSFETs. The inductive
load switching capability of the AAT4901 eliminates the
need for external diodes during commutation time. In
applications where rotation is always in the same direc-
tion, a single half-bridge AAT4900 can be used to drive
a DC motor. If needed to control the rotation in both
directions, full-bridge motor control circuits can be
applied as shown in Figure 4. In this configuration the
motor can be controlled to run clockwise, counter-clock-
wise, stop rapidly (“regeneration” braking) or free run
(coast) to a stop.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
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ENA
1
IN
2
3ENB
4ENC
END
OUTA
OUTB
GND
8
7
6
5
AAT4901-3
VIN: 2.0V ~ 5.5V
CIN
L1
L2
CO
R1
R2
VOUT
VCC
GND
FB
PWM1
SW1
PWM2
SW2
2 -Phase
DC/DC
Controller
IL1
IL2
IL1 + IL2
On/Off (EN)
Figure 2: AAT4901 in 2-Phase Synchronous Buck Converter Power Stage.
OUTA
OUTB
IL1
IL2
IL1+IL2
Figure 3: Output Current Ripple Reduction (IL1+IL2) due to 2-Phase Cancellation.
When the voltage applied between the DC motor by the
input(s) logic control is reversed, it could change the
rotation direction. When both outputs (OUTA/OUTB) are
floating, the motor winding acts as a regeneration; the
current inside the motor winding would continue to flow
into the input capacitor through the internal MOSFET
parasitic diode and decay to zero rapidly, stopping the
motor rapidly. When both outputs are connected to the
input supply (or ground) simultaneously, the motor
coasts and the winding current decays slowly due to the
winding resistor until the motor free runs to a stop.
The speed of a DC motor is directly proportional to the
supply voltage. It can be controlled by simply adjusting
the voltage sent to the motor, but this is quite inefficient.
A better method is to switch the motor’s supply on and
off rapidly. If the switching is fast enough, the motor
doesn’t notice it, it only notices the average effect. The
time it takes a motor to speed up and slow down under
switching conditions is dependent on the inertia of the
rotor (basically how heavy it is) and the amount of fric-
tion and load torque. Figure 5 shows the speed of a motor
that is being turned on and off at a fairly low switching
frequency. The average speed is around 150, although it
varies quite a bit. If the supply voltage is switched quick-
ly enough, the motor will not have time to change speed
much and the speed will be quite steady. When the duty
cycle (D = TON/T) is increased, the average speed of the
motor increases. Thus the speed is controlled by the duty
cycle of the PWM (Pulse Width Modulation).
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
4901.2010.01.1.2 13
www.analogictech.com
MM
ENA
1
IN
2
3ENB
4N/C
N/C
OUTA
OUTB
GND
8
7
6
5
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
AAT4901-2
MM
MM
ENA
1
IN
2
3ENB
4N/C
N/C
OUTA
OUTB
GND
8
7
6
5
AAT4901-4
ENA
IN
ENB
ENC
END
OUTA
OUTB
GND
AAT4901-3
ENA
IN
ENB
N/C
N/C
OUTA
OUTB
GND
AAT4901-1
VIN: 2.0~5.5V
VIN: 2.0~5.5V
VIN: 2.0~5.5V VIN: 2.0~5.5V
C1
4.7µF/16V
C1
4.7µF/16V
C1
4.7µF/16V
C1
4.7µF/16V
MM
CLK/DIR
CLK/DIR
CLK/DIR
CLK/DIR
CLK/DIR
EN
EN
Brake
Brake
Figure 4: Full-Bridge Motor Driver Using AAT4901.
Time
Motor Speed
100
50
0
150
200
Supply Voltage
0
5
10
15
20
Motor Speed
Supply Voltage
Ton
T
Figure 5: Motor Speed vs. Supply Voltage.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
14 4901.2010.01.1.2
www.analogictech.com
The minimum switching frequency is chosen based on
motor characteristics (the equivalent inductance and the
parasitic series resistor) and the percentage of current
variation to the average current specified. The minimum
switching frequency is in direct proportion to the para-
sitic series resister, and in inverse proportion to the
equivalent inductance and allowable current ripple.
When driving a high-voltage DC motor, external high-
voltage MOSFETs are needed to commutate the motor.
In this application, the AAT4901 can be configured as a
double-ended gate driver, as illustrated in Figure 6.
The full-bridge power stage operates the motor drive con-
trol as shown in Figure 7. Each side of the motor can be
connected either to the battery's positive terminal or to
the battery's negative terminal through the switch. Note
that only one MOSFET on each side of the motor may be
turned on at any one time; otherwise the high-side and
low-side MOSFETs will short out the battery and burn out.
There is also a diode connected in reverse across the field
winding, to absorb the current in the field winding when
all four MOSFETs in the bridge are turned off.
During period (A), to make the motor run forwards, Q4
is turned on, and Q1 has the PWM signal applied to it.
The current path is shown in blue in Figure 7. At period
(B) Q4 is kept on, so when the Q1 PWM signal is off, cur-
rent can continue to flow around the bottom loop through
Q3’s parasitic diode. At period (C), to make the motor
run backwards or control the speed, Q3 is turned on, and
Q2 has the PWM signal applied to it. At period (D), Q3 is
kept on, so when the Q2 PWM signal is off, current can
continue to flow around the bottom loop through Q4’s
parasitic diode. At period (E), when the motor is running
forwards for example, the motor is now acting as a gen-
erator and forcing current through its armature, through
Q2’s diode, through the battery (thereby charging the
battery) and back through Q3’s diode.
ENA
1
IN
2
3ENB
4N/C(ENC)
N/C(END)
OUTA
OUTB
GND
8
7
6
5
AAT4901-1,-2,-4
(-3)
VIN: 5.0V
C1
4.7µF/16V
CLK1
High-Voltage
Rail
to Moto
r
CLK2
Figure 6: Double-Ended Gate Driver.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
4901.2010.01.1.2 15
www.analogictech.com
Dual Channel, High Speed,
High Current 3-State Line Driver
The AAT4901-3 is ideally suited for dual channel, high
speed, high current 3-state line driver applications such
as CCD clock drivers. The low quiescent power dissipation
makes this part attractive in battery powered products.
The 3A peak drive capability also makes the AAT4901-3
an excellent choice for driving high speed capacitive
lines. The 20ns fast switching/delay time allows clocking
speeds up to 10MHz.
Dual Low-Side MOSFET Driver
The AAT4901-3 is also ideally suited for dual low-side
MOSFET driver applications due to its dual independent
half-bridge output configuration. It can be used in a
push-pull topology as illustrated in Figure 9 or in other
applications which require the ability to drive the
MOSFETs quickly, due to the AAT4901's extremely low
RDS(ON) (220m typ.) and very fast propagation time
(20ns typ.)
Lf
armature
La
Field winding
VBAT +
VBAT -
Q1
Q3
Q2
Q4
Lf
armature
La
Field winding
VBAT +
VBAT -
Q1
Q3
Q2
Q4
Lf
armature
La
Field winding
VBAT +
VBAT -
Q1
Q3
Q2
Q4
Lf
armature
La
Field winding
VBAT +
VBAT -
Q1
Q3
Q2
Q4
Ia
Period (A)
Ia
Period (B)
Period (C) Period (D)
Ia Ia
Lf
armature
La
Field winding
VBAT +
VBAT -
Q1
Q3
Q2
Q4
Period (E)
Ia
Figure 7: Full-Bridge Motor Drive Control.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
16 4901.2010.01.1.2
www.analogictech.com
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
16 4901.2010.01.1.2
www.analogictech.com
ENA
ENB
3-State
ENC
3-State END
IN
OUTA
OUTB
GND
Figure 8: AAT4901-3 Dual Channel High-Speed High-Current 3-State Line Driver.
VIN
+
+
VOUT
ENA
1
IN
2
3ENB
4ENC
END
OUTA
OUTB
GND
8
7
6
5
AAT4901-3
VCC: 5.0V
C1
4.7µF/16V
PWM A
EN
PWM B
Figure 9: Push-Pull Topology MOSFET Driver with AAT4901.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
4901.2010.01.1.2 17
www.analogictech.com
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
4901.2010.01.1.2 17
www.analogictech.com
VIN
2
1
3JP 1
2
1
3JP 2
2
1
3JP 3
2
1
3JP 4
GND
GND
M1
M2
M3
M4
OUTB
OUTA
Motor
Load
L1
C2
L2
C3
TP1
TP2
C1
GND
C
ENA
1IN 2
ENB
3
ENC
4
GND 5
OUTA 7
OUTB 6
END
8
AAT4901
U1
4.7μF
Figure 10: AAT4901 Evaluation Board Schematic.
Figure 11: AAT4901 Evaluation Board Figure 12: AAT4901 Evaluation Board
Top Side Layout. Bottom Side Layout.
Component Part Number Description Manufacturer
U1 AAT4901 Buffered Power Full-Bridge AnalogicTech
C1 GRM21BR61C475KA88 Cap Ceramic 4.7F 0805 X5R 16V 10% Murata
C2, C3 Not Populated
L1, L2 Not Populated
Load Not Populated
Table 1: AAT4901 Evaluation Board Bill of Materials.
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
18 4901.2010.01.1.2
www.analogictech.com
AAT4901
Buffered Power Full-BridgeFastSwitchTM
PRODUCT DATASHEET
18 4901.2010.01.1.2
www.analogictech.com
Advanced Analogic Technologies, Inc.
3230 Scott Boulevard, Santa Clara, CA 95054
Phone (408) 737-4600
Fax (408) 737-4611
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual
property rights are implied. AnalogicTech reserves the right to make changes to their products or specifi cations or to discontinue any product or service without notice. Except as provided in AnalogicTech’s terms and
conditions of sale, AnalogicTech assumes no liability whatsoever, and AnalogicTech disclaims any express or implied warranty relating to the sale and/or use of AnalogicTech products including liability or warranties
relating to fi tness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. In order to minimize risks associated with the customer’s applications, adequate
design and operating safeguards must be provided by the customer to minimize inherent or procedural hazards. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to
support this warranty. Specifi c testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other
brand and product names appearing in this document are registered trademarks or trademarks of their respective holders.
Ordering Information
Package Marking1Part Number (Tape and Reel)2
SC70JW-8 D2RYY AAT4901IJS-1-T1
SC70JW-8 D3RYY AAT4901IJS-2-T1
SC70JW-8 D4RYY AAT4901IJS-3-T1
SC70JW-8 2SRYY AAT4901IJS-4-T1
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor
products that are in compliance with current RoHS standards, including the requirement that lead not
exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at
http://www.analogictech.com/aboutus/quality.php.
Package Information
SC70JW-8
0.225
±
0.075
0.45
±
0.10
0.05
±
0.05
2.10
±
0.30
2.00
±
0.20
7
°
±
3
°
4
°
±
4
°
1.75
±
0.10
0.85
±
0.15
0.15
±
0.05
1.10 MAX
0.100
2.20
±
0.20
0.048REF
0.50 BSC 0.50 BSC 0.50 BSC
All measurements in millimeters.
1. XXGYY: XX denotes Device code, G denotes assembly code, and YY denotes date code.
2. Sample stock is generally held on part numbers listed in BOLD.
